by Wendy Koch, USA TODAY

by Wendy Koch, USA TODAY

On Thursday, two of the nation's largest environmental websites plan to announce their partnership and expanded use of atypical advertising to attract new sponsors, including Wal-Mart.

Mother Nature Network, co-founded by Rolling Stones' keyboardist Chuck Leavell in 2009, and TreeHugger, bought by Discovery Communications in 2007, have agreed to a jointly owned partnership. Together, they have more than 7 million monthly visitors and 26 full-time staffers.

"This is a true example of one plus one adding up to three," says Joel Babbit, co-founder and CEO of Mother Nature Network who will serve as CEO of the combined companies. He says search engines will rank the websites' content higher because of their expanded reach.

He says the websites will continue to operate independently for the "immediate future" but after a month or two, they may merge. "It won't have the word 'eco' or 'green' in it," he says, adding that those terms are overused in the environmental space. He says he may need to expand staff but also can't rule out layoffs.

"It's a really good partnership for us," says TreeHugger editor-in-chief Meaghan O'Neill, who helped found the website in 2004. She says many decisions are still to be made about how the two companies will partner, but she says Mother Nature Network's unique approach to advertising "could be a good thing for us."

Mother Nature Network (MNN) doesn't sell traditional ads but rather year-long $300,000 sponsorships for each of its websites' segments or channels. For example, Mercedes-Benz is the sponsor of its transportation one and AT&T backs its "gadgets and electronics" one. MNN produces a series of videos that the sponsors rotate in a designated spot on the website.

Babbit says companies want to develop relationships with readers so they welcome his approach, which he'll expand to TreeHugger. He says MNN has increased its sponsor revenue, despite a still-sluggish economy, from $2.2 million in 2009 to $3 million in 2010, $4.1 million in 2011 and a projected $7 million (combined with TreeHugger) this year.

In January, he says, Wal-Mart is becoming an especially large sponsor of a new editorial section that will highlight how people, products, companies and organizations are helping the environment.

'It's a growing trend," says Rick Edmonds, media business analyst at the Poynter Institute, a non-profit school for journalists, of the sponsorship approach. He says several companies are experimenting with that model, because typical pop-up ads and banners aren't popular with readers or bringing in enough revenue.

"There's no reason big companies can't do that, too," Edmonds says.

While TreeHugger focuses mostly on environmental issues, Mother Nature Network has broadened its purview to include personal safety and finance as well as health and family activities. Babbit says the environment is only one part of a "responsible lifestyle," adding that people who smoke and drink heavily are rarely adamant about protecting the planet.